Particularly throughout the industralized world, frozen foods have now become commonly accepted and encompass a wide variety of different types of food, many of which require different freezing techniques. This worldwide expansion of the present food industry and the spectrum of foods which are now marketed in a frozen state has resulted in a great diversity and sophistication of freezing methods and in-line production equipment.
Regardless however of the type of frozen foods involved or the particular technique or equipment employed in preparing the frozen foods, it is generally recognized that the food should be frozen as quickly as possible in order to preserve the natural taste and appearance of the food. To accomplish this rapid freezing of the food product, however, requires different procedures and devices depending upon the type of foods being frozen.
For example, in one technique the prepared food product is spread on a metal mesh belt through which subfreezing air is passed to make intimate contact with the food product. In another method used to accomplish the same result, the food product is spread on trays which are placed in tiers on a trolley which is then placed in a refrigerating room and blasts of cold air directed over the surface of the food. In yet another commonly practiced method, a fluidized bed is employed in which a current of cold air passes up through a belt or conveyor tray carrying the food particles thereby producing a moving fluidized bed in which the food particles are slightly suspended in the air current above the tray or belt while they are frozen.
The particular use, however, of any of these systems will largely depend upon the type of foods being treated. For example, it will be appreciated that large pieces of meat, poultry or fish are not suitably frozen using the fluidized bed technique which is suitable however for small items such as peas or diced vegetables. It will further be appreciated that heretofore each of the various freezing techniques employed to freeze different kinds of foods has required an entirely different and expensive piece of equipment. Thus, the manufacturer of frozen foods must assemble at considerable expense a wide variety of pieces of equipment for freezing the different kinds of food which he processes despite the fact that some of this large and expensive equipment may only be used for a short time due to the brief growing season as in the case of vegetables, fruits and berries.
Freezing equipment heretofore employed in the frozen food industry, in addition to lacking desirable diversity, has also had the disadvantage that it has been awkward and inconvenient to clean and maintain. This has become an increasingly serious problem in view of more stringent hygenic standards required by government agencies.
It is therefore an object of the present invention to provide a new and improved method and apparatus for freezing a wide variety of foods which heretofore required different freezing techniques and equipment.
It is further object of the present invention to provide a food freezing device which permits the alternative use of several different types of food conveyor systems while utilizing a common air handling and refrigeration means.
It is still a further object of the present invention to provide a food freezing device in which different types of air handling units can be readily interchanged.
Still a further object of the present invention is to provide a food freezing device and method in which both the air handling and refrigeration units can be readily inspected, cleaned, removed or interchanged with other units.
Still a further object of the present invention is to provide a food freezer having improved air flow characteristics which can be readily altered depending upon processing requirements.